Sensory neuropathy (SN) is a severe neurological disease affecting
young Border Collies for which there is no treatment. Affected dogs
progressively lose the sensation in their limbs due to the
degeneration of sensory and motor nerve cells and have to be
euthanised.

The onset of the disease is usually between two and seven months
of age and clinical signs include knuckling of the feet,
self-mutilation wounds (caused by excessive chewing or licking due
to the lack of feeling in the limbs) and a progressive lack of
coordination (ataxia).

SN is currently a rare disease but cases have been seen worldwide
in the UK, US, Belgium, Japan and Italy and, before a case is seen,
it is impossible to know which lines contain carriers.

To help Border Collie owners and breeders combat this debilitating
disease The Kennel Club Genetics Centre at the Animal Health Trust
has identified the genetic mutation responsible for SN and a DNA
test, priced at £48, will be available to order from the AHT DNA
Testing Service from Monday 27 April. A Border Collie combination
test, testing for SN, trapped neutrophil syndrome and Vitamin B12
deficiency will also be available to order from Monday 27 April at
a discounted price of £68 for all three tests.

Dr Oliver Forman, Genetics Researcher at the AHT and lead of the
SN investigation, said: "It's really important for the Border
Collie population that we've been able to identify the genetic
mutation responsible for this debilitating disease and develop a
DNA test so quickly.

"Although this is a relatively rare condition, DNA testing offers
the chance of eliminating this disease from the breed, and will
avoid the risk of it becoming a bigger problem in the future.
As the condition is rare it's impossible to predict which lines
contain carriers so DNA testing is the only way to ensure carrier
to carrier matings are avoided, which could result in litters
containing affected puppies."

Finding the mutation

Scientists at the AHT have been researching the genetic basis of
this disease in the Border Collie since two affected dogs were
diagnosed by neurologists in the AHT's Small Animal Centre,
providing DNA samples to begin a genetic investigation. A third DNA
sample was provided from the University of Glasgow.

The three samples were compared to the DNA of 170 Border Collies
whose DNA has been submitted to the AHT from owners to aid its
epilepsy research in the Border Collie. This extensive bank of DNA
was crucial in enabling the AHT to identify which chromosome
contained the genetic mutation for SN as quickly as possible. Once
this was identified the chromosome was sequenced to find the faulty
gene responsible for SN.

Once the mutation had been found the AHT worked in collaboration
with the University of Glasgow and the University of Missouri to
test DNA from a total of 11 affected dogs, all of which were
confirmed to have two copies of the mutation identified by
scientists at the AHT.

Oliver added: "This break-through discovery shows how the vets and
scientists at the AHT are able to work together to investigate
health conditions observed in the clinics and to collaborate with
other research institutions to further research projects. Our
thanks go to everyone involved, it is hoped that fewer dogs will be
born with this horrible condition in the future."

Caroline Kisko, Kennel Club Secretary, said: "We are delighted
that the Kennel Club Genetics Centre at the Animal Health Trust has
made this breakthrough, which will undoubtedly improve the health
of Border Collies by enabling breeders to help eradicate this nasty
condition from their breed.

"Scientists at the Kennel Club Genetics Centre at the AHT are
making great strides in their work, which goes a long way in
improving dog health across the board and we would encourage Border
Collie breeders to utilise the new DNA test to help cement the next
stage in their breed's health - eradicating this horrible
disease."

Combined test

To make SN testing easier and more affordable for owners the AHT
is offering a combined test for three conditions affecting Border
Collies.

Dogs affected by trapped neutrophil syndrome suffer from an
impaired immune system due to a reduced number of white blood cells
released into the bloodstream and have to be euthanised at a young
age. Vitamin B12 deficiency or Imerslund-Gräsbeck Syndrome (IGS),
is a treatable disease which affects the blood and nervous system
which prevents young dogs from thriving and can make a dog
anaemic.

All three conditions require two copies of the faulty gene in
order for a dog to be genetically affected. Dogs with one copy of
the faulty gene will be asymptomatic carriers and dogs with no
copies of the faulty gene are classified as clear.

Oliver said: "Although all of these conditions are relatively
rare, when we ran the three tests on a random selection of DNA
samples from Border Collies we found 6% were carriers for trapped
neutrophil syndrome and 8% were carriers for vitamin B12
deficiency, so it is always worth testing for peace of mind about
your dog's health. No additional carriers of SN were identified,
but we know there are carriers in the population because of the
cases we seen in the clinics.

"We know that there can be a lot of different things to test your
dog for prior to breeding but health testing is really important
for the breed as a whole as well as for individual dogs and we hope
a lot of people will make the most of this combined offer."